Bending brake



Mmh 2, 1943. R. F. DEHN 2,312,755

` BENDING BRAKE 'Filed -May 11, 1940 i INVENTOR.

ATT() Y5 Patented Mar. 2, 1943 UNTED S"l`Al'l`ES.l TENT O--FFICE BnNnmG BRAKE Roy F. Dehm, Cleveland, Ohio, assigner to The Cleveland Crane. & Engineering Company, Wickliffe,` Ohio, a corporation of Ohio z,application,liliay.v 111,1940, Serial No. 334,647

zClafima (Cl. 153-21) The present for bending metal platesvand the like and. hasV for its object the provision of a bending brake.

comprising means for indicating the. stresser. load to whichA it is orhasbeen. subjected.

Bending brakes of thetype referred to usually.

comprise a frame having a horizontal openingvv extending the entire length thereof, adieplate..

or abutment supported by the frame andlocated at the lower side of said opening, a ram. supe. ported directly above the die plate or abutment,

and meansl for producing a relative movement.`

between the die plate or abutment and ram, usually including a` crank and pitman, mecha.

nisrn operatively connected to the rameandto.

the ram. Because of the force amplication inherent in their operatingrmechanism, the ramsr of most heavy duty bending brakes of the chan. acter referred to are capable of exerting a stress between the ram and die plate or abutment beyond the ability of the brake to withstand. the.

same without permanent injury.

The principal object of thepresent invention. is the provision of anovel bending brake of the invention relates toU bending.. brakes of the particular type especially vadapted.

general character` referred toA comprising means including mechanism operatively connected. to

the frame adjacent the dies for conveniently in..

dicating the force or pressureexerted by the ram during the operation of the press brake sothat.

overloading of the press can beavoided.

Another object of the present, invention is the provision of a bending brake of the characterv referred to comprising means for indicating the.

maximum force which has been applied by the ram between resettings of the indicator.

The present invention resides in certain def tails of construction and combinations4 and yar,- rangements of parts and further objects and advantages thereof will be apparent to those skilled in the art to which the invention relatesl from the following description of the preferred embodiment thereof described with reference to the accompanying drawing forming apart of this specification in which similar reference characters designate corresponding parts throughout the Various views and in which:

Fig. 1 is a perspective View of a bending brake embodying the present invention:

Fig. 2 is an enlarged View of a portion of Fig. 1; and

Fig. 3 is an enlarged view of a portion of Fig. 2 with parts omitted for the purpose of clearness.

Referring to the drawing, the press brake shown therein comprises a frame A of welded-up steel plates, including end plates Ifland I;I, and;

a front plate or lower leaf I2 which carries the lower die plate I3. The upper surface ofthe die plate I3 forms the supporting surface or abrite.,v

ment for the lower die or-punch Iii as the case may be. The upper die or punch i6 lis connected, to the lower end of the upper-leaf or ram I]- slidably supported above the die plate. I3 and., adapted to be reciprocated toward and fromthe, same by some suitable operating mechanism,V The mechanism shown for reciprocating the ram.. comprises adjustabley pitmans I8- connected. to...

the ram Il and tosuitablecranks. on a. crank shaft I9 rotatably supported in the frame Vadjacent the upper frontl edge thereof.

crank shaft I9 is rotated by an electric motor.

housed within the frame A and operatively. conf., nected thereto by a clutch 29, the engagement;

of which is under the control of a foot treadle 21.I

If desired, the clutch maybe. automaticallydisf.4v engaged upon each revolution of. the crankshaft..

Each of the end plates'. or members I0 andfjII;Y is cut away adjacent the dies to form a throat;`

which provides clearance for materialgbeing operated upon and the edges of these plates,which@r are formed by the cut-outportion are reenforcedg by heavy C-shaped forgings 22 weldedthereto and to the front plate or leaf I2. The:particular..- press brake shown is similar inu construction` to;v that disclosed in U. S. Patent to` William Wehr, No. 2,199,864, to whichreferencegisInadcg for a more detailed disclosure thereof.;

Because of the inherent force amplification, of ram operating mechanisms. of the character employed in heavy duty bending brakes,y these machines are capable of exerting a load or, forcer. between the dies, and in turn between the partswhich support or carry the dies, beyond. the,...

ability of the various parts towithstand the same without failure.

force applied by the ram. This means is preferably in some form which will make it convenient for the operator to know whether or not the bending brake is being operated at or above its capacity. The preferred construction of bending brake shown comprises a micrometer distance measuring dial indicator 25 secured to the end plate Ill adjacent the upper edge of the cut-out portion thereof, the operating plunger 26 of which dial indicator is engaged by the head The;

Failure usually appears inthe. form of permanent deformation or rupture-cfu the end plates adjacent their cut-out portions.r` as this is usually the weakestpartof the frame...r

The present invention provides: aA bending-v brakehaving novel meana-forindicating then of an adjustable screw 21 fixed to the upper end of a C-shaped rigid member 28 which embraces or spans the cut-out portion. The lower end of the member 28 is welded as at 29 to the plate I or otherwise fixed thereto at a point adjacent to the die plate I3 for the lower die. The upper end of the member 28 is loosely held in position by a bolt 30 threaded into a suitably tapped aperture in the end plate l0, the shank of which extends through an elongated aperture 3l in the member 28. A member 32 carried by the end plate l0 and including a portion overhanging the member 28 intermediate its ends assist in holding the latter in position.

The construction is such that the dial indicator measures the strain effected in that y portion of the frame between the lower end of ,A

the member 28 and the place where the dial indicator is connected to the end plate, in other Words, the dial indicator measures the deflection across the opening of the throat. This deflection is used to indicate the load or force applied by the ram. The dial indicator is preferably calibrated in tons force applied by the ram, in which event the deflection across the throat is used to give a direct reading of the force exerted or applied between the dies. Preferably the dial indicator is also provided with a follower hand 33 actuated from the main hand 34. If desired, the follower hand can be so arranged that it cannot be reset, or the dial indicator and the upper end of the member which operate the same can be enclosed within a metal case or the like provided with a lock so that it cannot be reset or tampered with by unauthorized persons. As shown, the dial indicator 25 is enclosed within a-metal case 35 xed to the frame A by means including a lock 36. The micrometer distance measuring dial indicator shown will not be described in detail. Sufce it to say that it is of commercial construction modified to include a follower hand and calibrated in tons force applied between the dies.

The frame of the press brake of the present invention is preferably of one-piece construction as shown in the drawing as in this event the deflection across the opening of the throat will accurately reflect the load or force applied or exerted between the dies. In the case of a ribbed frame, this would not necessarily be true because of movement between the various parts of the frame. While in the preferred construction shown indicating means has been applied to only one end of the press brake, it is to be understood that the right-hand end of the press brake which does not show in the drawing is preferably of the same construction as the left-hand end which is shown.

From the foregoing description of the preferred embodiment of the invention, it will be apparent that the objects heretofore enumer-V ated and others have been attained and that there has been provided a press brake including novel indicating means by virtue of which the operator or his employer may know whether or not the bending brake is being overloaded. While the preferred embodiment of the invention has been described with considerable detail, I do not wish to be limited to the particular construction shown which may be varied within the scope of this invention and it is my intention to cover hereby all adaptations, modifications and uses thereof which come within the practice of those skilled in the art to which the invention relates.

Having thus described my invention what I claim is:

1. In a bending brake of the character described, the combination of a frame comprising vertically positioned horizontally spaced stress resisting end members having aligned openings in their front vertical edges forming a throat adapted to receive work to be operated upon, and an abutment member adapted to support a die or punch adjacent to the lower side of said throat; a movable ram or leaf located at the opposite side of said throat from said abutment member and slibably supported by Said frame for vertical movement towards and from said abutment member; said ram or leaf being adapted to carry a die or punch on the lower side thereof; means connected to said frame and supported thereby for reciprocating said ram or leaf; a rigid member extending around said throat, means for xedly connecting one end of said rigid member to said frame at one side of said throat; and a dial indicator means connected to said frame at the opposite side of said throat and to the adjacent end of said rigid member for indicating the force exerted between said abutment member and said ram or leaf member.

2. In a bending brake of the character described, the combination of: a frame comprising vertically positioned horizontally spaced stress resisting end members having aligned openings in their front vertical edges forming a throat adapted to receive work to be operated upon, and an abutment member adapted to support a die or punch adjacent to the lower side of said throat; a movable ram or leaf located at the opposite side of said throat from said abutment member and slidably supported by said frame for vertical movement towards and from said abutment member; said ram or leaf being adapted to carry a die or punch on the lower side thereof; means connected to said frame and supported thereby for reciprocating said ram or leaf; a rigid member extending around said throat, means for xedly connecting one end of said rigid member to said frame at one side of said throat; and a dial indicator means connected to vsaid frame at the opposite side of said throat and to the adjacent end of said rigid member for indicating the force exerted between said abutment member and said ramor leaf member, said dial indicator having means for indicating the maximum force exerted between said abutment member and said ram or leaf between resettings of said indicator.

ROY F. DEHN. 

